we have 2 female beagles who were litter mates. They are 2 years old, and one was the biggest of the litter and the alpha, and the other was the runt. When they were little, the runt would howl and bark, and now she stays quiet, and lets her big sister make all the noise. Is this normal? Is it part of their pack mentality? She is not mute. She will growl and bark when she is by herself.